In the field of, e.g., motor drive technology, etc., for hybrid cars or electric cars, etc., a relatively large current is used and there is thus a demand for electric current detection devices capable of non-contact measurement of a high current. Some of such electric current detection devices use a magnetism detector element(s) to detect strength of a magnetic field generated by an electric current to be measured, thereby detecting the magnitude of the electric current to be measured. The magnetism detector element is, e.g., a Hall element using the Hall effect, an AMR element using an anisotropic magnetoresistive (AMR) effect, a GMR element using a giant magnetoresistive (GMR) effect or a TMR element using a tunnel magnetoresistive (TMR) effect, etc.
The magnetism detector elements are arranged closed to an electric current path of a measuring object, and wires for inputting/outputting signals to/from the magnetism detector elements are also arranged closed to the electric current path. Therefore, when the current value in the electric current path varies at a high frequency of about several tens kHz to several hundred kHz, induced electromotive force occurs between the wires of the magnetism detector elements and induced electromotive force noise is superimposed on the outputs of the magnetism detector elements, causing a decrease in detection accuracy. Conventionally, when two magnetism detector elements are used, impedances of conductive patterns of two output wires are adjusted so that the noise component clue to voltage variation is cancelled (see, e.g., PTL 1).